NAME
Plack::Middleware::Throttle::Lite - Requests throttling for Plack
VERSION
version 0.02
DESCRIPTION
This middleware allows to restrict access to PSGI application based on
requests per unit of time (hour/day at the moment). Implemetation of the
middleware inspired by Plack::Middleware::Throttle.
FEATURES
Blacklisting
Requests from specified IPs (including ranges) or CIDRs are rejects
immediately with response 403 Forbidden.
Whitelisting
Requests from specified IPs (including ranges) or CIDRs allows to
get an unlimited access to the application.
Flexible and simple throttling policy
Access to an application might be configured on either by hourly or
by daily basis.
Routes configuration
Flexible settings for routes matching based on regular expressions.
Various storage backends
There is an API which allows to write and use any database or cache
system to manipulate throttling data.
Very lightweight
It will not install "a-half-of-CPAN" or "heavy" dependencies!
SYNOPSYS
# inside your app.psgi
my $app = builder {
enable 'Throttle::Lite',
limits => '100 req/hour', backend => 'Simple',
routes => [ qr{^/(host|item)/search}, qr{^/users/add} ],
blacklist => [ '127.0.0.9/32', '10.90.90.90-10.90.90.92', '8.8.8.8', '192.168.0.10/31' ];
sub {
[ 200, ['Content-Type' => 'text/plain'], [ 'OK' ] ];
}
};
CONFIGURATION OPTIONS
limits
By this option is defined the throttling policy. At the moment, there
are two variants in limiting of requests: "per hour" and "per day".
Value of maximum requests might be pointed as number and measuring units
(hour, day). Some examples:
# restrict to 520 request in an hour
enable 'Throttle::Lite', limits => '520 req/hour';
# ..maybe 10000 requests in a day?
enable 'Throttle::Lite', limits => '10000 req/day';
Also valid more short constructions:
# should not exceed 315 request in an hour
enable 'Throttle::Lite', limits => '315 r/h';
# ..19999 requests in a day
enable 'Throttle::Lite', limits => '19999 r/d';
Or even
# ..it works
enable 'Throttle::Lite', limits => '51 req per hour';
# ..this one also okay
enable 'Throttle::Lite', limits => '99 r per d';
# ..and this
enable 'Throttle::Lite', limits => '72 r per hour';
# ..no space between number and units also allowed
enable 'Throttle::Lite', limits => '34r/hour';
# ..oops! and this one does not work, yet ;-) sorry..
enable 'Throttle::Lite', limits => '100rph';
If this option is omitted, there are some defaults will be assigned. For
maximum requests default value will be 199 and measuring units -
req/hour. So this option must be set to desired value to have get
correct throttling policy.
When a client exceeds rate limit, middleware returns a 429 Too Many
Requests response with an associated "Rate Limit Exceeded" message in
the response body.
backend
Storage backend and its configuration options. Accepted values either
string or list reference contains backend name and options as hash
reference. Backend name can be pointed in short module name or in fully
qualified module name. If module name does not belongs to
Plack::Middleware::Throttle::Lite::Backend namespace it can be pointed
by adding + (plus) sign before name.
# means Plack::Middleware::Throttle::Lite::Backend::Simple
enable 'Throttle::Lite', backend => 'Simple';
# means Plack::Middleware::Throttle::Lite::Backend::OwnStore
enable 'Throttle::Lite', backend => 'OwnStore';
# means My::Own::Throttle::Backend
enable 'Throttle::Lite', backend => '+My::Own::Throttle::Backend';
If backend name passed as list reference, the first element will be
handle as backend module and the second as options passed to constructor
during initialization.
# treat as Plack::Middleware::Throttle::Lite::Backend::Anything
enable 'Throttle::Lite',
backend => [
'Anything' => { server => 'anything.example.com', port => 23250 }
];
# ..as My::Own::Any
enable 'Throttle::Lite',
backend => [
'+My::Own::Any' => { server => 'anything.example.com', port => 23250 }
];
If no backend specified then will be used in-memory backend
Plack::Middleware::Throttle::Lite::Backend::Simple shipped with this
distribution.
routes
URL pattern to match request to throttle. Accepted values are scalar
(e.g. "/api"), regex ("qr{^/(host|item)/search}") or a list reference
with scalar/regex elements. Below some examples:
# passing routes as scalar..
enable 'Throttle::Lite',
routes => '/api';
# ..as regex
enable 'Throttle::Lite',
routes => qr{^/api/(user|host)};
# ..shaken, not stirred
enable 'Throttle::Lite',
routes => [
'/foo/bar',
qr{^/(host|item)s/search},
qr{^/users/add},
qr{^/Api/Login}i,
'/knock/knock',
];
All requests will be passed through (won't be handled by this
middleware) if no routes given.
blacklist
Blacklist is aimed to restrict some bad guys to have get access to
application which uses this middleware. IP addresses can be passed
either as string or as list of strings in a different forms. It might be
simple IP address (quad-dotted notation), IP block in CIDR notation or
range of IP addresses (delimited by a hyphen).
# passing IP address as string..
enable 'Throttle::Lite',
blacklist => '127.0.0.1';
# ..as CIDR block
enable 'Throttle::Lite',
blacklist => '192.168.10.0/27';
# ..as a range of IPs
enable 'Throttle::Lite',
blacklist => '10.90.90.90-10.90.90.92';
# ..stirred, not shaken
enable 'Throttle::Lite',
blacklist => [
'192.168.1.12/32',
'10.90.90.90-10.90.90.92',
'127.0.0.1',
'10.104.32.64/29',
];
More details in Net::CIDR::Lite.
When a client's IP address is in the blacklist, middleware by default
returns a 403 Forbidden response with an associated "IP Address
Blacklisted" message in the response body.
Warning! Blacklist has higher priority than "whitelist".
whitelist
Whitelist is aimed to grant some good guys to have get access to
application which uses this middleware. Whitelisted client's IP address
will receive unlimited access to application. In generated header which
is pointed to maximum requests for whitelisted guy will be *unlimited*
instead of actually given maximum requests.
Rules of configuration IP addresses for whitelist the same as for the
"blacklist".
Warning! Whitelist has lower priority than "blacklist". Be sure that IP
does not exists in blacklist by adding IP to whitelist.
header_prefix
This one allows to change prefix in output headers. A value should be
passed as string. It will be normalized before using. Any alpha-numeric
characters and spaces are allowed. The parts of passed string will be
capitalized and joined with a hyphen.
header_prefix => ' tom di*ck harry ' # goes to X-Tom-Dick-Harry-Limit, X-Tom-Dick-Harry-Used, ..
header_prefix => 'lucky 13' # ..X-Lucky-13-Limit, X-Lucky-13-Used, ..
header_prefix => '' # ..X-Throttle-Lite-Limit, X-Throttle-Lite-Used, ..
header_prefix => '$ @ # & * /| ; ' # also would be X-Throttle-Lite-Limit, X-Throttle-Lite-Used, ..
header_prefix => 'a-b-c' # ..X-Abc-Limit, X-Abc-Used, ..
header_prefix => '2.71828182846' # ..X-271828182846-Limit, X-271828182846-Used, ..
This option is not required. Default value is Throttle-Lite. Header
prefix will be set to the default value in cases of specified value
won't pass checks. This option does not affect the Retry-After response
header.
METHODS
prepare_app
See Plack::Middleware
call
See Plack::Middleware
modify_headers
Adds extra headers to each throttled response such as maximum requests
(X-Throttle-Lite-Limit), measuring units (X-Throttle-Lite-Units),
requests done (X-Throttle-Lite-Used). If maximum requests is equal to
requests done X-Throttle-Lite-Expire and Retry-After headers will be
injected.
Headers (except of Retry-After) might be customized by using
configuration option "header_prefix".
reject_request
Rejects incoming request with specific code and reason. It might be
either request from blacklisted IP or throttled one.
have_to_throttle
Checks if requested PATH_INFO matches the routes list and should be
throttled.
is_remote_blacklisted
Checks if the requester's IP exists in the blacklist.
is_remote_whitelisted
Checks if the requester's IP exists in the whitelist.
is_allowed
Checks if client is not exceeded maximum allowed requests.
requester_id
Builds unique (as possible) indentificator of the client based on its IP
address and name.
BUGS
Please report any bugs or feature requests through the web interface at
SEE ALSO
Plack
Plack::Middleware
RFC 2616
Hypertext Transfer Protocol - HTTP/1.1. Section 14.37: "Retry-After"
RFC 6585
Additional HTTP Status Codes. Section 4: "429 Too Many Requests"
AUTHOR
Anton Gerasimov
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Anton Gerasimov.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.